In conventional working platforms, the respective bearing frame is equipped with a plate-shaped cover, which generally consists of a laminated plywood and is riveted to the bearing frame. The numerous perforations in the plywood, during the use of the working platform, results in time in an enlargement of the rivet bores in the plywood so that the cover is unable to contribute to the stiffness of the working platform and is not given consideration during its static performance calculation. The shifting of the cover on the bearing frame, even if only slightly increasing, contributes moreover to a reduction in the workman's stepping safety during the use of the working platform.
It has therefore also already been suggested that the plywood sheets be bounded by a metallic holding frame resting on the flanges of the bearing frame, in particular when the cover at its holding frame is thereby riveted to the bearing frame by means of connecting elements. The holding frame is less subject to permanent deformation in the bores for the connecting elements than the plywood sheets so that looseness due to wear in the area of these connecting elements can indeed be avoided even in the case of high stress on the working platform. However, such a working platform is expensive.
Instead it has been also known for a long time to design the bearing surface with simple steel floors of perforated plates, which are bent at their longitudinal sides to form short, vertical crosspiece strips fastened to the bearing frames resting on the same. In order to achieve a sufficient resistance force to rotational movement, these edging crosspiece strips are bent at least one more time, and as a rule several times to the inside so that the bearing surface is defined on both sides by a U-shaped to a box-shaped, more or less solid, at all positions, however, an open hollow cross section. The manufacture of such bent footplates from bending blanks is personnel and cost intensive, and the footplates are, because of the not closed and non-closeable hollow sections, not as torsional-resistant as desired. Furthermore, it cannot be avoided during operation of the work platform that dirt and building rubble penetrates through the perforated plate into the hollow cross sections and can only be removed with great difficulty and effort.
It is also known that at least the longitudinal bearing members consist of a preferably extruded hollow section, which is approximately rectangular in cross section and each of which is composed of two parallel vertical crosspieces and two horizontal flanges. Such a box-shaped design of the longitudinal bearing members results in a torsion-free design of the bearing frame, in particular, when at the corner joints of the bearing frame the crosspieces of the cross-bearing members are each carried through to the outer crosspiece of the longitudinal bearing members and are welded to the flanges and/or crosspieces of the longitudinal bearing members. Such a corner joint has in this manner a very robust design and can be highly stressed. Furthermore, this type of design has the advantage that the ends of the bearing frame already at its longitudinal sides form closed surfaces.
The purpose of the invention is to design a working platform of the general type identified in detail above to be very reliable in operation using simple means, and, moreover, in such a manner that the bearing surface permanently improves the stiffness of the working platform and can be included in the static performance calculations. Moreover, it is intended to be easy to manufacture and to be easily connectable to the bearing frame. At the same time care is taken to safely prevent an accumulation of dirt and building rubble in the working platform. Furthermore, an arrangement is possible such that several working platforms are reciprocally sufficiently locked when they are stored stacked one on top of the other.